How much oil to use...

[Joel]

I've looked in all my manuals, engine specs, etc...  Nothing tells me how much or what type of oil to put in the crankcase.   I'm GUESSING a high quality 10W30 and approx 5 quarts (depending upon what the dipstick reads).  Somebody out there throw me a bone and tell me the answer to these annoying questions.

Thanks guys!

[Mike Harry]

I know a GM 350 holds 5 quarts and my INDMAR 350 is a GM block-pan-and heads so I go with 5 quarts.

Another question in this general area though, you cant go 3000 miles on an oil change like a car, so how long should you go as a rule of thumb in a boat?

[phil]

My Ford 351 Windsor takes about 5 1/2 qts to fill it just below the full mark. I use Valvoline VR1 which is formulated with a lot of zinc. It's especially made for flat tappet cams. IT's 15w 40.  I would certainly go with the VR1 is you have a flat tappet cam.

[Joel]

Phil,

I have the Ford 351 c.i. / 250 hp as well...  I'll go with 5 & 1/2 quarts...  Thanks!

[skiboatdriver]

I have an Indmar 351 H.O. that takes 6 quarts to be full. I have been using 10w-40. As far as how often to change it, that depends. We do a lot of idleing/motoring around and pull skiers maybe every weekend on an open lake. I try to change it twice per season; once before we put the boat in the water (April) and once mid season (July).